Maybe it helps to explain, that matter does not have any fixed size. An atom is mostly an empty space, inhabited by a few kind of stable and force-carrying particles. If matter is compressed, it will become an extremely hot "soup" of more basic particles, such as the limited space and high energy level permits to exist. At these extreme temperatures the sub-atomic structure changes and inside suns that permits creation of heavy elements out of lighter elements.

So you might try to find similarities between Big Bang and an explosion of a supernova, only BB created the basic hydrogen out of nobody knows what (energy), while supernovae are stars which took the basic hydrogen, made heavier elements out of it and exploded them further, so that planets rich on elements and various chemistry can exist, like ours.

That is the best...when questions and answers lead to more questions and more answers and expand ones preconceived notions of things as seemingly obvious as what a day is, and how we know what a day was millions of years ago, of what time is and means. And in this case, whether what we know, and why we know it, can square with the bible.

One way to imagine the speed of light, in a more accessible way, is to compare it to the distance of the sun, rather than galaxies or other stars. Explain that it takes light ~8 minutes to travel the ~92 million miles from the sun’s surface to the earth. So what we see when we see the Sun is actually the light that left the surface of the Sun ~8 minutes ago, so you are seeing the Sun as the light on the surface of it appeared ~8 minutes ago. We can’t see the surface of things, we see the light that leaves that thing and makes it to us, so we can’t see the surface of the Sun, until the light from it’s surface travels the ~92 million miles to reach our eyes, but it is still the light as it looked when it left. Then explain, if the Sun, hypothetically, disappeared right now, the light that last left the surface of the Sun, and it’s heat energy, would still be traveling for the next ~8 minutes to the earth. For that entire ~8 minute journey, after the Sun hypothetically disappeared, we would still receiving it’s light, and heat energy, so that in every respect we would still experience it as being there even thought it’s been absent entirely for the past ~8 minutes.

Then compare that concept to a star 50 thousand light years away. Explain that the light we are seeing now is the light that left it as it was 50 thousand years ago, in the same way that the light we see from the Sun is the light from the Sun as it appeared ~8 minutes ago. Also explain that if that star went supernova right now, we would not see the light of the explosion until it has traveled the 50 thousand light years. That some of those stars may not even exist anymore. A star you look at tonight, may have exploded and died 25 thousand years ago, and we will still have 25 thousand years before we even know. Once we see that supernova, from 50 thousand light years away, we are seeing an event that happened 50 thousand years ago, in effect looking back in time.

The farther away an object is, the farther back in time we are looking because the farther that light must travel. If we see an object that is at a distance that would take light 13 billion light years to travel to us, what we are seeing is that object as it appeared as light left it’s surface 13 billion years ago, so we are seeing what it look like 13 billion years ago, not as it looks like today. We wouldn’t be able to tell what it looks like today, right now, for billions of years more, when it’s light then reaches us.

I like this guy because he talks about the evidence. I didn't even know that there were untouched intergalactic clouds. It's amazing that we have evidence for the big bang and that we know that it happened.